An X-Band Dielectric Rod Antenna for Subdermal Tumor Heating to Assist Electroporation-Mediated DNA Delivery

Abstract

An end-fire dielectric rod antenna is proposed as a heating device for integration with an array of electroporation electrodes in order to enable efficient delivery of DNA into the cells that comprise subcutaneous tumors. A 5-7 °C temperature elevation of tumors that are located near the fat-muscle boundary and 3-7 mm below the skin surface can be achieved in a short period of time without damaging surrounding tissues. This capability is demonstrated through a combination of a directional antenna applicator operating at 8 GHz, and utilization of forced air cooling of the outer surface (skin layer). The directionality of the antenna is improved by cladding its high permittivity core with 3D printed, low permittivity dielectric material. Experimental data using a pork skin-fat-muscle tissue show that the desired temperature elevation at the tumor location is obtained after 2.5 W RF illumination for 3 minutes, which is in good agreement with electro-thermal simulations. With the addition of realistic human body model parameters to the same simulation setup, the results indicate that tumors can be uniformly heated with 3 minutes of illumination at 2.5 W input power while keeping the surrounding healthy tissues at a safe temperature.